Let Package-Kit's FetchFileJob handle redirects.

* additionally, drop duplicate setting of CURLOPT_PROGRESSFUNCTION.
Put haiku repository onto image.

* Now that system updates seem to work properly, put the haiku
  repository config and cache file onto the image automatically.
* Adjust URL of haiku repository (it is currently redirected
  to some other URL at download.haiku-os.org, but that will be
  changed later).